[Some properties of complexes formed by small heat shock proteins with denatured actin].
We applied different methods to analyze the effects of the recombinant wild-type small heat shock protein with an apparent molecular mass of 27 kD (Hsp27-wt) and its S15,78,82D mutant (Hsp27-3D), which mimics the naturally occurring phosphorylation of this protein, on the thermal denaturation and aggregation of F-actin. It has been shown that, at the weight ratio of Hsp27/actin equal to 1/4, both Hsp27-wt and Hsp27-3D do not affect the thermal unfolding of F-actin but effectively prevent the aggregation of F-actin by forming soluble complexes with denatured actin. The formation of these complexes occurs upon heating and accompanies the F-actin thermal denaturation. It is known that Hsp27-wt forms high-molecular-mass oligomers, whereas Hsp27-3D forms small dimers or tetramers. However, the complexes formed by Hsp27-wt and Hsp27-3D with denatured actin did not differ in their size, as measured by dynamic light scattering, and demonstrated the same hydrodynamic radius of 17-18 nm. On the other hand, the sedimentation coefficients of these complexes were distributed within the range 10-45 S in the case of Hsp27-3D and 18-60 S in the case of Hsp27-wt. Thus, the ability of Hsp27 to form soluble complexes with denatured actin does not significantly depend on the initial oligomeric state of Hsp27.
Pivovarova
A V
AV
Chebotareva
N A
NA
Guseev
N B
NB
Levitskiĭ
D I
DI
D000199:Actins / Q000737:chemistry*; D000818:Animals; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D018832:Molecular Chaperones; D046912:Multiprotein Complexes / Q000737:chemistry*; D009363:Neoplasm Proteins / Q000737:chemistry*; D011489:Protein Denaturation; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry; D012995:Solubility
D000199:Actins; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D011994:Recombinant Proteins